This invention relates to a method and apparatus for embossing diffraction gratings in conformance with a predetermined code on to a strip of reflective plastic which is later imbedded in a record medium like a "credit card" for use in security systems to identify the user of the card.
This invention is related to copending U.S. applications, Ser. No. 588,937 filed on June 20, 1975, Ser. No. 611,377 filed on Sept. 8, 1975, and Ser. No. 611,378 filed on Sept. 8, 1975, all of which said copending applications have been assigned to the same assignee as this application.
Recent developments in security or financial systems, credit systems, funds transfer systems, and the like, rely heavily on the use of record media or "credit cards" having magnetic stripes or tracks thereon with various data such as account number, credit limits, credit status, credit available for use, and the like, being recorded magnetically on the stripes. Such systems have to be designed to avoid or minimize the fraudulent use of such record media or credit cards.
One of the ways in which fraudulent use of such credit cards is made is to counterfeit the cards by mass reproduction techniques which "skim" or transfer the data magnetically recorded on a valid card to a fraudulent one.
The problem of trying to prevent the unauthorized duplication of or use of valid credit cards used in financial, credit or security systems, and the like, is a very extensive one, as evidenced by the variety of different techniques discussed in said copending application Ser. No. 588,937.
Said copending application, Ser. No. 611,377, discloses a method and apparatus for producing superimposed optical or diffraction grating masters, which in turn, are used to produce superimposed gratings for use in a record medium or "credit card", and said copending application is incorporated by reference herein.
Said copending application, Ser. No. 611,378 discloses a special type of reader which is used for reading a record medium containing coded data in the form of diffraction gratings.
Said copending applications Ser. Nos. 588,937 and 611,377 disclose methods for producing "credit cards" having diffraction gratings thereon by techniques which are essentially manually operated.
In order to produce "credit cards" of the types disclosed in said copending applications in the large quantities which are necessary for acceptance by the banking industry, for example, it is necessary that the method for producing the "credit cards" be automated to a larger extent. Some prior art general embossing techniques are shown in U.S. Pat. Nos. 3,502,761, 3,636,147 and 3,861,299.